Conventional message signatures can be used for the purpose of demonstrating the authenticity of a digital transmission (e.g., a message or a document). For example, a digital signature that is determined to be valid gives a recipient of a message with that signature reason to believe that the message was created by a known sender, and was not altered during the course of the message transmission. Such signatures are commonly used to facilitate secure financial transactions, data transmissions, and in other cases where the integrity of a transmission is critical. Furthermore, message signatures can be used for non-repudiation purposes (i.e., the sender of a message cannot reasonably claim that they did not send a message that includes their signature).
Some digital message signing approaches employ cryptographic techniques (e.g., asymmetric cryptographic algorithms). For example, a conventional public key encryption scheme can be used to sign messages. For example, a party holding a public key can determine if a message was signed using the corresponding private key. In other examples, two parties may share a secret key, and each party who knows the key can verify that the signature was made by another party that knows the key.
One approach to generation for cryptographic keys makes use of fabrication variations between silicon devices, which provide a way of regenerating a device-specific key without requiring its storage. For example, physical uncloneable function (PUF) circuits have been used, typically in conjunction with error correction techniques to deal with intra-device variation, to regenerate keys that can be used for signing a message. In this way, a recipient can determine that a message was sent by particular hardware device.
In some applications, the security of knowing that a message as signed by a known device (e.g., a transmission endpoint) is important, but does not warrant existing techniques that use PUF-based generation of cryptographic keys. For example, in high speed of in low power devices, such prior techniques key generation techniques may have limitations.